The present invention relates generally to the field of cutting or sawing harder materials such as concrete, brick, stone, etc., and more specifically relates to a cutting member, a link for a cutting member and a method of forming a cutting member, of the kinds indicated in the preambles of patent claims 1, 11 and 12 respectively.
For cutting harder materials of the kind indicated in the introduction there are many available alternatives, whereby a basic distinction is made between portable saws and saws connected to or supported by a frame. Portable units, predominantly for cutting concrete and bricks, are presently available on the market in the shape of circular saws, chain saws or so called ring saws, which as specified by the name employ a circular blade, a chain and an eccentrically driven ring respectively for carrying a number of cutters or cutting elements provided at regular distances from each other. Of said mentioned saws the circular blade saws and ring saws suffer from a restricted cutting depth due to practical limitations with regard to the diameter of the ring or the circular blade, and they also suffer from the disadvantage that when they are employed for forming an opening in for instance concrete they produce a substantial eccessive cutting or sawing at the corners, which is not acceptable primarily due to the danger of cutting off reinforcement bars and the decreased strength associated therewith. Saws having a chain, i.e. basically designed by interconnected links in the same manner as a saw chain for sawing into wood, do indeed have the advantage compared to circular blade saws and ring saws that they eliminate the problem of eccessive cutting and at the same time allow for a greater sawing or cutting depth to be obtained, but instead they suffer from the disadvantage that the cost of replacing cutters or cutting elements on the chain is comparatively high and in many cases unacceptable.
Saws connected to frames or stands are available both for cutting concrete and brick and for cutting stone or rock, and within this category there are likewise saws which work with a chain of a conventional type and which therefore suffer from the above-mentioned drawback (see for instance SE, B, 8603681-1). For saws connected to stands cutting members have also been developed which consist of cutting elements threaded onto a wire or the like and primarily intended for use in "floating" cutting, i.e. without any underlying guide in the shape of a saw guide bar or the like. Such cutting members are described for instance in SE, B, 359 767 and EP-A-0 160 625 and as the support unit they employ a wire onto which sleeve-like cutting elements are threaded, said cutting elements being provided with a cutting surface around their periphery. Apart from the fact that it is practically impossible to replace individual worn out cutting elements on these known cutting members, due to the design of the cutting members these are only possible to use for "floating" cutting. Due to the fact that the cutting member according to the first-mentioned document is formed by providing cutting elements freely rotatable on the wire and carrying members firmly connected to the wire, alternatingly on the wire the saw member becomes very stiff so that it can only be bent with a relatively large radius. The same applies in principle also to the last-mentioned one of the above named documents, by which the entire wire and the cutting elements are encapsulated in a layer of thermoplastic material, which likewise renders the saw member rigid, i.e. having a high flexural rigidity.
Finally, EP-A-0 376 128 discloses a cutting member of the kind mentioned in the introduction, from which the present invention starts. In this document a cutting member is described which is in the shape of a wire as the support unit and which has cutting elements provided integral therewith. Thereby, the cutting elements are firmly connected to cutting element carriers which in turn are rigidly attached to the wire, primarily by means of soldering or brazing. When brazing or soldering such a cutting element carrier to a wire the solder will however creep out a relatively long distance into the wire and will thereby stiffen the wire such that it cannot be bent with any small radius. It is stated in very general terms in the above-mentioned document that the cutting element carriers may be attached to the wire by applying pressure thereto, but it is not clear in any detail how this should be performed. In such a case a direct locking of the cutting element carriers to the wire along their entire length also takes place, which in turn means that the wire in its entirety becomes relatively bending stiff. Moreover the direct locking of the cutting element carriers to the wire causes problems and high costs when replacing damaged or worn out cutting elements.